A method of this general type is disclosed in the magazine "Laser Focus World", 1991, pp 93-99. In this article an overview of the six different conventional methods for producing microlenses and microlens arrays is described. The closest method includes the production of an approximately lens-shaped structure on the surface of a substrate by means of photolithographic masking and subsequent etching, which is subjected to heat treatment, because of which a minor mass transport results, which, with certain materials, leads to qualitatively good lenses. The lithography is performed with a plurality of masks that are respectively aligned, so that the totality of the sequentially etched and stepped structures approximately form the lens. The heat treatment leads to complete melting of the lens material and also of the entire carrier substrate. During this melting the surface tension produces a deformation of the entire surface and of the lens mass as well as of the surrounding substrate; although the stepped structure is reduced, the optical parameters of the lens are changed drastically, leading to optical errors and to severe dispersions and deviations of the lens characteristics with respect to a respectively given characteristic.
Moreover, it is known from the magazine "Spektrum der Wissenschaft Spectrum of Science!", 1992, pp. 44-50, Veldkamp et al, Binary Optics, to etch a planar diffractive lens into the planar face of a planar-convex refractive lens, where the opposing color aberrations of the refractive and the diffractive optics mutually compensate each other and color fidelity is attained over a broad spectral scope. The etched refractive lens, however, produces a light scatter by means of its etched end face that reduces the image contrast. To avoid this error over a wide wave range, a large number of masking and etching steps are used, for example up to twelve, wherein the etching is performed at a decreasing step height. This means high production costs and causes a considerable amount of rejections, i.e. unsatisfactory product which is waste.